tweak

To make minor adjustments; perfect: Is the President going to tweak emissions for seven years and then let them rip?/ He used the core of the President's plan, and from that he did some tweaking(1990s+)

[perhaps a memory of the days when a crystal was tweaked with a ''cat's whisker'' in order to tune a primitive radio receiver]

The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.Copyright (C) 2007 by HarperCollins Publishers.Cite This Source